WO2003077968A2

WO2003077968A2 - Method of treating a medical condition with a portable medication delivery device

Info

Publication number: WO2003077968A2
Application number: PCT/US2003/003130
Authority: WO
Inventors: Scott Forster Percy
Original assignee: Eli Lilly And Company
Priority date: 2002-03-13
Filing date: 2003-02-27
Publication date: 2003-09-25
Also published as: AU2003208948A1

Description

METHOD OF TREATING A MEDICAL CONDITION WITH A PORTABLE MEDICATION DELIVERY DEVICE

BACKGROUND OF THE INVENTION The present invention pertains to medication delivery, and, in particular, to a method of using a portable medication delivery device to treat a medical condition. Patients suffering from a number of different diseases frequently must inject themselves with medication. To allow a person to conveniently and accurately self- administer medicine, a variety of devices broadly known as injector pens or injection pens have been developed. Generally, these pens are equipped with a cartridge including a piston and containing a multi-dose quantity of liquid medication. A drive member, extending from within a base of the injector pen and operably connected with typically more rearward mechanisms of the pen that control drive member motion, is movable forward to advance the piston in the cartridge in such a manner to dispense the contained medication from an outlet at the opposite cartridge end, typically through a needle that penetrates a stopper at that opposite end. In disposable pens, after a pen has been utilized to exhaust the supply of medication within the cartridge, the entire pen is discarded by a user, who then begins using a new replacement pen. In reusable pens, after a pen has been utilized to exhaust the supply of medication within the cartridge, the pen is disassembled to allow replacement of the spent cartridge with a fresh cartridge, and then the pen is reassembled for it subsequent use.

One problem with injection pens is that some users find unsettling the prospect of inserting a needle into one's own skin. To address this situation, at least one automatic needle insertion device has been brought to the market. This device, which is disclosed in U.S. Patent No. 5,980,491, includes a cartridge holder that is loadable with a cartridge and which is movably mounted within a housing of the device. After a dose setting and injection portion of an injection pen is mounted to the cartridge holder, the device is cocked by moving the cartridge holder in a proximal direction to a cocked position against the force of a spring. Then, the distal end of the device is placed against the user's skin, and the user presses a trigger button adjacent the proximal end of the device to cause the cartridge holder to be spring-biased forward from its cocked position, such that a needle mounted on the cartridge holder extends beyond the distal end of the device and penetrates the user's skin. The user can then manually operate the dose setting and injection portion of the pen, which pen portion typically has previously been manipulated to set a dose to be delivered by its operation, to deliver medication through the skin- penetrating needle. One shortcoming of this device is that while the pen needle is inserted in the user, the user may have to walk his/her hand up along the device from a position at which that hand was comfortably able to manually actuate the trigger button, to a position at which that hand can comfortably operate the pen portion to deliver medication. Furthermore, the user has to consciously press the trigger button with his/her finger in order to cause the needle insertion to occur, which may not be the easiest thing for some people to convince themselves to do. Another known automatic needle insertion device, but one which is designed for use with a common syringe and not an injection pen, also utilizes a manually activated trigger button to drive a spring-biased syringe distally. However, such trigger button is only operable after the distal end of the device has been pressed against the injection site sufficiently hard to cause the distal part of the device's multi-part housing to move relative to a proximal part of the device housing to unlock the trigger button. While useful to prevent an accidental advancement of the syringe, this device still suffers from the shortcoming of requiring a user to consciously press the trigger button with her finger in order to cause the needle insertion to commence.

Thus, it would be desirable to provide a method that can overcome these and potentially other shortcomings of the prior art.

BRIEF SUMMARY OF THE INVENTION The present invention encompasses a method of treating a medical condition in a person, which method includes the steps of: loading an injection pen into an automatic needle insertion device; cocking the automatic needle insertion device to prepare for shifting the injection pen relative to a body of the device in a distal direction from a first position to a second position; moving the cocked automatic needle insertion device with loaded injection pen into a position at which a distal end of an actuation sleeve of the device is positioned against the skin of the person around an injection site; and, manually advancing the cocked automatic needle insertion device with loaded injection pen in the distal direction toward the injection site such that the actuation sleeve shifts proximally relative to the advancing body until the actuation sleeve automatically triggers the device to shift the injection pen relative to the body of the device from the first position to the second position, wherein at the second position a needle of the injection pen extends beyond the distal end of the actuation sleeve and penetrates the skin of the person.

One advantage of the present invention is that a method can be provided for advancing a needled end of an injection pen so as to penetrate a user's skin without the user having to commence the needle advancement by consciously pressing or otherwise operating any trigger button with her thumb or other fingers.

Another advantage of the present invention is that a method can be provided in which a user is unlikely to prematurely fire an automatic needle insertion device merely in the process of gripping that device. BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other advantages and objects of this invention, and the manner of attaining them, will become more apparent, and the invention itself will be better understood by reference to the following description of an embodiment of the invention taking in conjunction with the accompanying drawings, wherein: Fig. 1 is a diagrammatic front view of an injection pen and an automatic needle insertion device that can be used to practice the method of the present invention, which injection pen and device have yet to be assembled together;

Fig. 2 is a diagrammatic front view of the injection pen and automatic needle insertion device of Fig. 1 after the loading of the injection pen into such device, and with the device in a ready or ready-to-be-cocked state;

Fig. 3 is a diagrammatic front view of the automatic needle insertion device with loaded injection pen of Fig. 2, after the injection pen has been pulled proximally to cock the device for use;

Fig. 4 is a diagrammatic front view of the cocked automatic needle insertion device with injection pen of Fig. 3 as the activation sleeve begins to retract by contact with the injection site;

Fig. 5 is a diagrammatic front view similar to the view of Fig. 4, but after the activation sleeve of the automatic needle insertion device has been fully retracted by contact with the injection site so as to cause the advancement of the injection pen in the distal direction; and

Fig. 6 is a diagrammatic cross-sectional view of the automatic activation sleeve on the distal end of the device body shown abstractly in dashed lines. Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent an embodiment of the present invention, the drawings are not necessarily to scale, and certain features may be exaggerated or omitted in some of the drawings in order to better illustrate and explain the present invention.

DETAILED DESCRIPTION OF THE INVENTION Referring now to Fig. 1, there is diagrammatically shown an uncapped injection pen and an automatic needle insertion device suitable for practicing the method of the present invention. The shown injection pen, generally designated 20, closely resembles a pen-type writing instrument in appearance, but the injection pen of the present invention may be configured to have a different appearance. Pen 20 is of a reusable or refillable variety and includes a replaceable cartridge filled with multiple doses of a medication. Pen 20 generally includes a distal portion 22 and a proximal portion 24. Distal portion 22 contains the medicinal fluid to be outlet at its distal end upon pen operation. Proximal portion 24 contains the dose setting and injecting mechanism used to selectively force the contained medicine from the needled end.

Distal portion 22 includes a retainer 28 which holds a cartridge 30 therein. Retainer 28 is removably mountable to pen proximal portion 24 to allow replacement of cartridge 30 when its contents are spent. A conventional pen-needle assembly, generally designated 38, is removeably mountable to the distal end of retainer 28. A cannula or injection needle 40 of pen-needle assembly 38 has a distal tip 42.

Cartridge 30 is of conventional design and defines a medicine-filled reservoir that is closed at its proximal end by a piston 31 that is axially slidably and sealably engaged with the cartridge interior wall to hold the fluid medication within the cartridge reservoir. Cartridge 30 can contain one of a variety of therapeutics, including but not limited to human growth hormone and insulin. The distal, outlet end of the cartridge reservoir is sealed by a not shown septum that is penetrated by the not shown proximal tip of needle 40 to provide a fluid flow outlet by which medicine within the cartridge can be dispensed from needle tip 42 during operation of pen 20. Pen proximal portion 24 includes a dose setting and injecting mechanism that permits any one of a number of quantities of medicine to be selected and then expelled from cartridge 30 at a given time through the attached injection needle assembly 38. In pen 20, this mechanism includes a manually operable dosage knob 44 and a mechanical drive mechanism 46 that is protectively housed within the housing 47 of pen portion 24 and operably connected to knob 44. Dosage knob 44 is rotatable in either direction to set the dose to be injected, or in other words control the distance a drive member will advance when the dosage knob 44 is plunged. Drive mechanism 46 includes a drive member 48 extendable from pen proximal portion 24 and which advances to shift piston 31 distally and force medication from cartridge 30 when dosage knob 44 is plunged after having been rotated to set a dose. Although dosage knob 44 may move out relative to the pen housing when rotated to increase the set dose, and then move in relative to the pen base when rotated to decrease the set dose, such axial motion during dose setting is a function of the drive mechanism to which it operatively attaches, and the dosage knob 44 need not so move.

The foregoing description of pen 20 is merely provided as background and is intended to be illustrative and not limiting in any way. A variety of injection pens are known in the art, for example which include different mechanisms for setting and administering doses, including mechanical as well as electromechanical mechanisms, and these pens may be used in automatic needle insertion devices particularly adapted to accommodate the design of such pens.

The shown automatic needle insertion device, generally designated 50, includes an elongated tubular body 52 made of plastic with an internal hollow 54 adapted to insertably receive injection pen 20. A plastic pen holder abstractly indicated at 56 is mounted in internal hollow 54 so as to be longitudinally shiftable between first and second axial positions relative to body 52. .Pen holder 54 is shown in Fig. 1 in the first or distal position. When pen holder 56 is moved to the second or proximal position during use as described further below, a biasing member of device 50, such as a metal coiled spring abstractly shown at 57 and acting between the body and the pen holder, applies a force on pen holder 56 tending to return it to the distal position. Pen holder 56 is adapted to receive and releasably hold injection pen 20 in an axially fixed fashion when pen 20 is loaded in device 50. Device 50 includes an automatic activation sleeve, generally designated 60, which is made of plastic and mounted over the distal end region of body 52. Sleeve 60 is slidably mounted on body 52 to be retractable from the extended position shown in Fig. 1, which retraction is designed to automatically cause a pen holder 56 previously cocked to its proximal position to be released to move to its distal position.

With reference to the cross-sectional view of sleeve 60 shown in Fig. 6, wherein the distal end of body 52 is shown merely abstractly and in dashed lines, sleeve 60 includes a collar portion 62 dimensioned to fit around body 52. An annular flange 64 inwardly projects from collar portion 62 and has a distal face 65 that can be pressed against a user's skin around the site where an injection is to occur. Central opening 66 of flange 64 permits needle 40 to be extended therethrough during use.

Sleeve 60 is biased distally relative to device body 52, such as by the metal coiled spring 68 that is shown acting between the proximal face of flange 64 and a shoulder 58 formed on the exterior periphery of body 52. Sleeve 60 is secured to body 52 so as to not be forced off the distal end thereof by spring 68. Such securing is shown performed by a radially inwardly extending tab 68 that fits in a groove in the body exterior, although other forms of securement may be used. Tab 68 also serves to key together sleeve 60 and body 52 to resist relative rotational movement during the full retraction of the sleeve.

The radially inward face of collar portion 62 is dimensioned to fit around body 52 and to actuate a control button mounted on body 52 and indicated abstractly at 59. Control button 59 is axially positioned within the axial ends of sleeve 60 at all times during use. Control button 59 is operatively coupled with pen holder 56 such that when sleeve 60 is fully retracted proximally to cause button 59 to be pressed inward by engagement with cam surface 63 of collar portion 62, the previously cocked pen holder is released so as to allow it to be spring biased from its proximal position to the distal position.

Automatic needle insertion device 50 may be equipped with a locking system that prevents sleeve 60 from being inadvertently retracted to fire a cocked device or to expose the needle of any loaded pen in an uncocked device when not being used. Such a system may include one or more cooperating detents and slots provided on sleeve 60 and body 52, which detent/slot combination is designed to prevent a needle exposing proximal retraction of sleeve 60 unless sleeve 60 has been manipulated by the user to a proper angular orientation relative to body 52. The sleeve manipulation may involve a small axial shifting of the sleeve relative to the body, which small shifting does not expose the needle of a pen in an uncocked device, before the sleeve can be rotated to the proper angular orientation, such as for example, the sleeve, in order to be unlocked for use, needing to be pushed proximally slightly and then rotated relative to the body 52 while being so pushed proximally.

The method of the present invention using injection pen 20 and automatic needle insertion device 50 will be further understood with reference to Figs. 1-5. References below to up and down are made with respect to those Figures, and do not limit the method to being practiced in such directions. These Figures also do not show the user, other than skin 100, to facilitate illustration.

The needled injection pen 20 is loaded into an uncocked device 50 by being inserted down through the open proximal end of device body 52 and into hollow 54. When fully inserted, pen 20 is engaged by pen holder 56 in a suitable fashion to be axially locked therein. At this time, injection needle 40 dose not extend beyond the distal end of sleeve 60 and is hidden from front view therein, and the pen/device assembly is arranged as shown in Fig. 2.

In order to prepare the pen/device assembly for needle insertion, the device is cocked. Specifically, while the user grips device body 52 in one hand, the other hand of the user grips the part of pen proximal portion 24 that projects above body 52 and pulls that portion 24 upwardly. Pen 20 along with pen holder 56 are moved upward against a resistance provided by internal spring 57 of the device. Pen holder 56 can be moved up until it reaches a proximal, cocked position at which it mechanically engages a not shown stop within body 52 which prevents the pen holder and pen from returning distally under the influence of the now compressed spring 57. At this time, with the pen needle 40 even further retracted from the distal end of sleeve 60, the pen/device assembly is arranged as shown in Fig. 3.

With the pen/device assembly cocked, the user can then rotate knob 44 to set the dose to be delivered by pen 20 when knob 44 is plunged, which set dose is displayed at 45. This dose setting naturally can be performed prior to the cocking step, but then the set dose would preferably be checked by the user before injection to ensure the dose knob was not inadvertently turned during the cocking process.

In order to inject medication from pen 20, the user first maneuvers the cocked pen/device assembly such that the distal face 65 of automatic activation sleeve 60 is first pressed against a user's skin 100 around the site at which the an injection is to occur. Because of the way device 50 provides for an automatic advancement of a needle, the actual motion of which advancement is not commenced by a finger pressing on a trigger button provided on the exposed periphery of the device, a user may hold the pen/device assembly during this maneuvering in nearly the same way the pen is held for injection, namely with her fingers clasped around proximal pen portion 24 and/or body 52, and with her thumb above dose knob 44, but preferably not pressing down on the knob in any way which may cause medication to be dispensed from the needle tip 42. Then, as the user applies a downward force on the held pen/device assembly, which downward force must be sufficient to begin compressing spring, the body 52 with held pen 20 is moved distally as sleeve 60 begins to slide up body 52. At an early stage of this sleeve retraction, the pen/device assembly is arranged as shown in Fig. 4.

As the user continues to urge the pen/device assembly downward, sleeve 60 remains in contact with skin 100 while continuing to slide up body 52 until cam surface 63 comes its contact with button 59 and forces the button inward, which inward motion causes device 50 to automatically release cocked pen holder 56. When released, pen holder 56 is driven downward by spring 57 so as to shift from the proximal position to its distal position, which pen holder movement drives pen 20 downward relative to device body 52 and sleeve 60 such that needle tip 42 pierces and then passes into the user's skin 100 after passing beyond the distal end of sleeve 60. At this time, the pen/device assembly is arranged as shown in Fig. 5. Then, to actually inject medicine, the user merely needs to plunge knob 44 downward, which plunging does not necessarily require the user to move her hand on the pen/device assembly from where it was positioned during the automatic needle insertion.

When the user finishes the injecting, simply lifting up the pen/device assembly perpendicular to the injection site will allow sleeve 60, due to spring 68, to return to its original position covering the needle. Pen 20 and device 50 can then be reused at a later date, preferably by changing the needle after first removing the pen from the pen holder.

This application is intended to cover any variations, uses or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains.

Claims

I CLAIM:

1. A method of treating a medical condition in a person, comprising the steps of: loading an injection pen into an automatic needle insertion device; cocking the automatic needle insertion device to prepare for shifting the injection pen relative to a body of the device in a distal direction from a first position to a second position; moving the cocked automatic needle insertion device with loaded injection pen into a position at which a distal end of an actuation sleeve of the device is positioned against the skin of the person around an injection site; and manually advancing the cocked automatic needle insertion device with loaded injection pen in the distal direction toward the injection site such that the actuation sleeve shifts proximally relative to the advancing body until the actuation sleeve automatically triggers the device to shift the injection pen relative to the body of the device from the first position to the second position, wherein at the second position a needle of the injection pen extends beyond the distal end of the actuation sleeve and penetrates the skin of the person.

2. The method of claim 1 further comprising the step of operating the injection pen after the needle has penetrated the skin of the person to deliver a desired dose of medication that is less than the total amount of medication contained in the injection pen.